This mini-review aimed to present an outlook on childhood obesity and leukemia in different regions of Brazil and explore a possible association between biological aspects related to adipose tissue and childhood cancer. We emphasized environmental factors that may influence cancer development and obesity and present studies showing different prevalences of these diseases in Brazilian regions. However, future studies are required to determine how environmental factors in these regions contribute to leukemia and obesity development in childhood and adolescence. Furthermore, we also emphasized that obesity may be associated with leukemia, considering the biological aspects of adipose tissue associated with disease development.